Apparatus for testing telephone calling dials



May 10, 1949. H. J. THIELK ER APPARATUS FOR TESTING TELEPHONE CALLING DIALS 2 Sheets-Sheet l I Filed June 5, 1947 INVENTOR H. J. TH/EL KER ATTORNEY Filed June 3, 1947 y 1949- Y H. J. THIELKER 2,470,002

APPARATUS FOR TESTING TELEPHONE CALLING DIALS 2 Sheets-Sheet 2 INVENTOR v H. .jJ. THIEL KER ATTORNEY Patented May 10, 1949 APPARATUS FOR TESTING TELEPHONE CALLING DIALS Henry J. Thielker,

Western Electric Company,

New York, N. Y., assignor to Incorporated, New

York, N. Y., a corporation of New York Application June 3, 1947, Serial No. 752,205

Claims.

This invention relates to testin apparatus, and. more particularly to apparatus for use in the mechanical adjustment and testing of telephone calling dials.

In the manufacture of calling dials for automatic telephone systems, the contact springs in the dial, which control the pulses transmitted in calling a subscriber or which short-circuit the telephone transmitter during the transmission of selecting impulses, must be adjusted to engage their corresponding springs at predetermined pressures. Similarly, the contact springs which open the talking circuit through the telephone receiver must be adjusted so that they break their circuit after the finger wheel of the dial has moved a predetermined amount from its normal position and before it has moved a slightly greater predetermined amount. The contacts which control the pulses transmitted in calling a subscriber must be adjusted so that they will, on the return of the finger wheel to normal to transmit impulses, be closed a predetermined amount of the time in proportion to the time they are ope n The adjustment of these contact springs to give them the desired operating characteristics necessitates bending the springs manually after they are assembled and, in bending one of the springs to give it the desired operating characteristic, another spring may be affected so that it will be out of proper adjustment due to the fact that some of the springs have to be adjusted for more than one characteristic.

In the past the mechanical adjustments have been made at the same time and within the same apparatus while electrical tests were made on the calling dials as disclosed in Christian Paulson Patent 2,267,129.

It is an object of the present invention to minimize the testing time for each telephone calling dial by providing a highly efficient and practical testing apparatus for mechanically testing and adjusting the dial.

In accordance with the object of the invention, the testing apparatus includes a base supporting a mountin plate recessed to receive the finger wheel of a telephone calling dial. A latch to secure the dial in place and hold the finger wheel against rotation is disposed on the mounting plate. An index gage is movable into any one of a series of known positions to cause relative movement of the casing and finger wheel of the dial to bring about operation of the various contact springs of the dial to determine their relationship between each other whereby the necessary adjustments may be made therein.

The index gage is notched to receive the finger stop of the dial whereby adjustment of the index gage in its arcuate path about the center of the dial will cause relative movement of the casing and finger wheel given distances from a normal position causing actuation of the dial to actuate the contact springs in a given sequence.

Other objects and advantages will be apparent from the following detailed description when considered in conjunction with the accompanying drawings, wherein Fig. 1 is an isometric view of the testing apparatus illustrating a telephone call dial mounted therein;

Fig. 2 is a side elevational view of the testing apparatus;

Fig. 3 is a top plan view of the mounting plate and associated mechanism of the testing apparatus;

Fig. 4 is an enlarged sectional view taken along the line i4 of Fig. 3; and

Fig. 5 is an enlarged fragmentary detailed view taken along the line 5-5 of Fi 3.

Referring now to the drawings, attention is first directed to the dial indicated generally at 20 which is to be tested. Although there are various types of telephone call dials, they are similar in general structure and operation and the selection of this particular type of dial will be sufficient to illustrate the invention. The dial 20 comprises a casing 2| on which there is mounted a governor 22 which controls the speed of the dial in returning to its normal position under spring propulsion, at which time the number dialed by a telephone user is transmitted over the telephone circuits to select the called telephone subscriber. A finger wheel 23 having ten finger holes 24 therein, is mounted in spaced relation to the casing 2| for manipulation by a subscriber in calling another subscriber of the telephone systern. Mounted upon the back of the casing 2| are a series of springs or contact members 25, 2B, 21, 28, 28 and 30. The contact member 25 and spring 26 are normally in engagement to complete a circuit through them which comprises a part of the talking circuit of the telephone system. The contact member 25 and spring 2'6 are, therefore, insulated one from another and supported at adjacent ends by a bracket 3|. The contact spring 25 and contact spring 21 are interconnected by an insulator 32 so that they move together when they are released from engagement with a camming member 33 actuated by the finger wheel of the dial, the springs 26 and 21 being normally biased to move the spring 26 out of engagement with the contact member and to move the spring 2'! into engagement with the contact mem- Engagement of the contact member 23 by the contact spring 27 short-circuits the transmitts-r unit of the telephone during dialing operations. The spring 29 and contact member 38 comprise the impulsing contacts which are made and broken to transmit impulses in the calling of one subscriber by another. These springs are biased so that they are normally closed and will be intermittently broken by a camming member operated under control of the finger wheel of the dial. The camming member 3L it will be understood, in the operation of this apparatus and in the ordinary operation of the telephone dial, is ineffective to break the contact between the contact member and spring 29 during the windup of the finger wheel 23 of the dial, but intermittently breaks this contact on the return of the finger wheel to normal.

The testing apparatus includes a base at with a horizontal portion 4| to rest upon a support, a central portion 42 curving upwardly and forwardly from the horizontal portion and a portion 43 disposed at a given angle with respect to the horizontal portion at the upper end of the central portion. Cushion-like feet M are mounted at spaced positions on the under surface of the horizontal portion 4| of the base to support the apparatus. A mounting plate 415. annular in general contour is centrally apertured at til, to receive the designation plate on the finger wheel of the dial, and recessed at 4? to receive the h and wheel 23. A cutaway portion 68 which extends through the mounting plate 45 and into the head portion 43 is provided for the finger stop ll? of the dial 20 to allow movement of the finger stop with the dial casing relative to the finger wheel. A clamping element 59 pivotally mounted at 5: on

the mounting plate 45 has an outwardly projecting portion 52 to be gripped by the operator and a lip 53 to extend over the finger wheel 23 be tween the finger wheel and the casing 2! to removably secure the finger wheel at a given position in the recess 4! and thus hold the dial in the apparatus. A pin 55 mounted in the plate and extending outwardly therefrom serves stop for the element 50 in its open position.

Elongate arcuate apertures 53 and 5?,

osed equal radial distances from the centerline of the mounting plate 45, are former in the mounting plate to receive supporting bolts or elements 58 at the ends of an index gage til. In this manner the index gage is movable a limited distance about the centerline of the mounting plate to cause movement of the dial casing and the me: anism housed in and supported thereby relative to the finger wheel. A positive connection is formed between the index gage Bill and the dial through the finger stop 49 of the dial, a notch or recess 52 being formed in the index gage to receive the finger stop.

Notches 63, 64, and 6B are formed in the outer surface of the index gage and may hereinafter be described as the #1, #2, #3, and #4 positions respectively. It will be noted by viewing Fig. 1 that the notches have the corresponding numbers embossed in the index gage adjacent thereto to identify the notches.

A latch is with a projection-to enter any of the notches G3 to 66, inclusive, is mounted on a slide H movably disposed in a radial notch 12 in the mounting plate 45. The slide has a narrow central portion substantially equal to the width of the notch '72, the upper and lower portions of the slide being wider to extend laterally over the upper and lower surfaces respectively of the mounting plate to maintain the slide for movement in a fixed path radially of the mounting plate A spring 74 normally urges the slide inwardly to cause the latch H! to enter any one of the notches 53 to 66, inclusive. One end of the spring is connected to a pin 15 disposed in an aperture of the mounting plate l5 and extended downwardly therefrom, while the other end of the spring is connected to a pin it carried by the slide l and extending downwardly therefrom.

The slide 'II is actuated to cause movement of the latch 10 toward and away from the index gage 60 by a cam lever ll. Spaced legs is of the cam lever straddle the slide H and are pivotally mounted on the slide through the aid of a pin it which extends through the slide and through apertures in the legs. The lower ends of the legs 78 have like cam surfaces 86, which engage the periphery of the mounting plate l-i upon each side of the notch 12 when the lever 'il' moved counterclockwise (Fig. 4), and projections Bl serving as stops at the lower ends of the legs to engage the under surface of the mounting plate The action of the cam surfaces 80 on the periphery of the mounting .plate 45 during counterclockwise movement of the lever 11 will move the slide ll outwardly, moving the latch ill with it free of any of the notches in the index gage M. The cam lever 11 functions also to hold the latch is in the open position awa from the index gage until it is rocked clockwise a given distance.

Considering now the function of the testing paratus, the apparatus is in the position shown in Fig. 3 prior to the mounting of a dial to be tested therein. The clamping element 5B is in the open position shown in this figure and the index gage 60 is set at the #1 position where itis held against movement by the latch ill. The dial 229 to be tested is then positioned in the apparatus, the finger wheel .23 being disposed in the recess ii of the mounting plate and the finger stop is being disposed in the notch 62 of the index gage To assure accurate positioning of the dial in the apparatus prior to locking the finger wheel, slight counterclockwise pressure is applied to the dial casing 2| to take up any slack, at the lower side of the finger stop 49 and the notch 62 and at the upper sideof the finger wheel 23 and the recess ll. With the dial held in this position, the clamping element 5.!) is rotated to the position shown in Fig. 1 where it will lock the finger wheel 1'13 in the recess, the lip 53 of the clamping element extending between the finger wheel and. the dial casing and applying necessary holding pressure on the finger wheel.

After the dial is mounted in the apparatus, the speed of the dial is tested by freeing the dial for partial rotation. This is accomplished by movement of the lever l1 into its open position to move the latch .1 0 free of the #1 position of the index gage .60. The dial casing may then be rotated agiven distance relative to the finger wheel moving with it the index-gage 60. When the dial casing has been moved the extreme distance, limited by the supporting bolts 58 of the index gage in the apertures 57, it may then be released and allowed to return to its normal position, the operator determining the speed of the return movement of the dial and adjusting the governor 22 accordingly, if adjustment is necessary.

The index gage is then set at the #4 position where it is .held .by the latch 10 entering the notch 66. When the dial is in this position, the tension vvl1. d of the pulse spring 29 is-checked and the necessary adjustments madetherein. Movement of the dial casing 2! relative to the finger wheel into the #4 position caused actuation of the camming member 33 to move it free of the contact spring 21, allowing this spring to move upwardly (Fig. 1) with the insulator 32 and free contact spring 26 to move away from the contact memher 215. If the desired actions of these contact springs and contact members do not take place, the necessary adjustments of the springs and contact members are made.

The index gage St is next moved to the #3 position to determine whether or not certain of the contact springs will be in given positions relative to their associated contact springs and members upon relative movement of the dial casing and finger wheel a given distance. In this position, the contact spring should open the circuit with contact member 25. The dial casing 2! with the index gage 50 is next moved to the #2 position, the operator observing during this motion of the dial casing whether or not contact spring 2'l moves free of contact member 28 prior to the movement of contact spring 25 into engagement with contact member 25. If the action of the contact springs relative to their contact members do not function in this order, the necessary adjustments are made.

The dial casing with the index gage 6% is next moved to the #1 or normal position, where all of the contact springs and their contact members are observed to determine whether or not they are in proper relationship, one with the other.

Other tests may be performed on the dial with the index gage fill free for relative movement of the dial casing and finger wheel to determine the action of certain parts of the dial.

It will be understood that with this apparatus all of the mechanical adjustments of the telephone calling dial may be made prior to any essential electrical tests, and in this manner, the time required for testing the dial has been greatly reduced. Through the aid of the apparatus, the dial casing with the contact springs and members, as well as the other mechanism of the dial may be moved into known positions relative to the finger wheel where certain actions should take place during these movements to cause making and breaking of circuits through the action of the dial mechanism on the contact springs and members. During commercial use of the dial in a telephone, the dial casing is held stationary while its mechanism is actuated by movement of the finger wheel. The same operations take place in the testing apparatus by holding the finger wheel against rotation and moving the dial casing into the known positions. In this manner, the operator may readily observe the actions of the various parts of. the dial when in the gaging positions or while the dial casing is moved from one position to another.

Although specific improvements or the invention have been shown and described, it will be un derstood that they are but illustrative and that various modifications may be made therein without departing from the scope and spirit of this invention as defined by the appended claims.

What is claimed is:

1. An apparatus for testing a telephone calling dial having a finger wheel rotatable relative to a dial casing, distances limited by a finger stop on the casing, the casing housing some of the actuating mechanism of the calling dial and supporting contact springs and members selectively actuated by the said mechanism from'their given normal positions during relative rotation of the finger wheel and casing, the apparatus comprising a mounting plate recessed to receive the finger wheel of the dial, an element to clamp the finger wheel against rotation in the recess, an index gage recessed to interengage the'finger stop of the dial, and means to support the index gage on the mounting plate for movement with the dial casing into known positions relative to the finger wheel.

2. An apparatus for testing a telephone calling dial having a finger wheel rotatable relative to a dial casing, distances limited by a finger stop on the casing, the casing housing some of the actuating mechanism of the calling dial and supccntact springs and members selectively actuated by the said mechanism from their given normal positions during relative rotation of the finger wheel and casing, the apparatus comprising a mounting plate recessed to receive the finger wheel of the dial, an element to clamp the finger wheel against rotation in the recess, an index gage recessed to interengage the finger stop of the dial, means to support the index gage on the mounting plate for movement with the dial easing into known positions relative to the finger wheel, and a latch carried by the mounting plate to secure the index gage and dial casing any or the said known positions.

3. An apparatus for testing a telephone calling dial having a finger wheel rotatable relative to a dial casing, distances limited by a finger stop on the casing, the casing housing some of the actuating mechanism of the calling dial and supporting contact springs and members selectively actuated by the said mechanism from their given normal. positions during relative rotation of the wheel and easing, the apparatus comprising a mounting plate recessed to receive the finger wheel of the dial, an index gage mounted on the mounting plate for movement into a norposition and into operating positions, a notch in the index gage to initially intereng-age the fir er stop of the dial at the normal position of index gage, and an element to clamp the finger wheel against rotation in the recess of the mounting plate.

4. An apparatus for testing a telephone calling dial having a finger wheel rotatable relative to a dial casing, distances limited by a finger stop on the casing. the casing housing some of the actuating mechanism of the calling dial and supporting contact springs and members selectively actuated by the said mechanism from their given normal positions during relative rotation of the finger wheel and casing, the apparatus comprising a mounting plate recessed to receive the finger wheel of the dial, an index gage mounted on the mounting plate for movement into a normal position and into operating positions, a notch in the index gage to initially interengage the finger stop of the dial at the normal position of the index gage. an element to clamp the finger wheel against rotation in the recess of the mounting plate, and a latch carried by the mounting plate to secure the index gage in the normal position and in any of the operating positions.

An apparatus for testing a telephone calling dial having a finger wheel rotatable relative to a dial casing, distances limited by a finger stop on the casing, the casing housing some of the actuating mechanism of the calling dial and supporting contact springs and members selectively actuated by the said mechanism from their given index gage, an element to clamp the finger Wheel 10 against rotation in the recess of the mounting plate, a latch carried by the mounting plate to secure the index gage in the normal position and in any of the operating positions, means normally urging the latch into latching position toward the index gage, and a cam lever to move the latch away from the index gage into open position.

HENRY J. THIELER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,796,805 Paulson Mar. 17, 1931 2,267,129 Paulson Dec. 23, 1941 

